​​http://www.elijahqi.win/archives/1896​​​
Time limit : 2sec / Memory limit : 256MB

Score : 300 points

Problem Statement
Snuke has decided to play with a six-sided die. Each of its six sides shows an integer 1 through 6, and two numbers on opposite sides always add up to 7.

Snuke will first put the die on the table with an arbitrary side facing upward, then repeatedly perform the following operation:

Operation: Rotate the die 90° toward one of the following directions: left, right, front (the die will come closer) and back (the die will go farther). Then, obtain y points where y is the number written in the side facing upward.
For example, let us consider the situation where the side showing 1 faces upward, the near side shows 5 and the right side shows 4, as illustrated in the figure. If the die is rotated toward the right as shown in the figure, the side showing 3 will face upward. Besides, the side showing 4 will face upward if the die is rotated toward the left, the side showing 2 will face upward if the die is rotated toward the front, and the side showing 5 will face upward if the die is rotated toward the back.

Find the minimum number of operation Snuke needs to perform in order to score at least x points in total.

Constraints
1≦x≦1015
x is an integer.
Input
The input is given from Standard Input in the following format:

x
Output
Print the answer.

Sample Input 1
Copy
7
Sample Output 1
Copy
2
Sample Input 2
Copy
149696127901
Sample Output 2
Copy
27217477801
把这个图的平面图画出来可以观察到 我最大的话就是5，6，5，6来回颠倒 然后看需要多少下 这以这个2步为以周期 我最后看剩余的数是否>6如果是 那么就方案+2否则非0就+1 0就直接输出即可

#include<cstdio>
long long x;
int main(){
    freopen("arc.in","r",stdin);
    scanf("%lld",&x);long long x1=x/11;x1<<=1;
    int left=x%11;if(left>6) x1+=2;else if (left) x1++;
    printf("%lld",x1);
    return 0;
}